How long does melatonin last?
Guess first. Then watch your dose against your own night: how high it goes, when it falls back under your own melatonin, and what's still there when the alarm goes off.
Guess first. How long do you think a 5 mg gummy at 11:30pm stays above your own melatonin?
4 hours
- Your own night
If a child swallowed melatonin, call Poison Control at 1-800-222-1222, and 911 if they can't be woken or have trouble breathing.
What your curve means
The dashed line is your own night. Above it, your blood holds more melatonin than a normal night ever does. A dose that's back under it a few hours after lights out has done its job and gone.
Still above it at your alarm? That's the usual reason for a heavy, groggy morning. Take less, take it earlier, or both. 0.5 to 1 mg is where to start, and 1 mg at 9pm is back under your own peak by 11:15pm to 12:15am.
A gummy is a range. The ribbon shows what it might really hold, from 74 to 347 percent of the label, so count a gummy as a bigger dose than it says, or switch to tablets from a brand that has each batch tested by an outside lab.
Each dose, taken at 10:30pm
| Dose | Peak, times a normal night | Back under your own night's peak | Tart cherries with the same melatonin |
|---|---|---|---|
| 0.3 mg | about 1 | level with it | 49 lb |
| 0.5 mg | about 1.7 | 11:50pm to 12:15am | 82 lb |
| 1 mg | about 3 | 12:45 to 1:45am | 164 lb |
| 3 mg | about 10 | 2:10 to 4:10am | 491 lb |
| 5 mg | about 17 | 2:50 to 5:15am | 819 lb |
| 10 mg | about 33 | 3:45 to 6:45am | 1,640 lb |
| 20 mg | about 67 | 4:40 to 8:15am | 3,280 lb |
One night, three curves
- Your own night, from 9:35pm
- 0.5 mg at 10:30pm, back by 11:50pm to 12:15am
- 10 mg at 10:30pm, back by 3:45 to 6:45am
How the curve works
0.3 mg brings blood levels to about a normal night's peak, so the height is your dose divided by 0.3. A tablet reaches its peak about 40 minutes after you swallow it, then halves about every 54 minutes. The dashed line halves every 1.5 hours instead, a slower band we added because in adults over 50, 3 mg stayed in the blood into daylight and melatonin may stay active longer as you age.
Gummies get a ribbon: in a 2023 test of 25 US gummies, 22 missed their label, holding 74 to 347 percent of it, most often 1.2 to 1.7 times. The cherries are Montmorency tart cherries at 13.46 nanograms of melatonin per gram.
Where the curve stops
The same 10 mg tablet peaked over 3 times higher in some men than in others, and the curve can't know which you are. Slow-release tablets spread the dose by design, so they aren't drawn. Your own night is a simple hill to set the dose against, not a measurement.
8 sources
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- Haimov I and others, Melatonin replacement therapy of elderly insomniacs, Sleep, 1995pubmed.ncbi.nlm.nih.gov
- Dollins AB and others, Effect of inducing nocturnal serum melatonin concentrations in daytime on sleep, mood, body temperature, and performance, PNAS, 1994pubmed.ncbi.nlm.nih.gov
- Andersen LP and others, Pharmacokinetics of oral and intravenous melatonin in healthy volunteers, BMC Pharmacology and Toxicology, 2016pubmed.ncbi.nlm.nih.gov
- National Center for Complementary and Integrative Health, Melatonin: What You Need To Know, last updated May 2024nccih.nih.gov
- Cohen PA and others, Quantity of melatonin and CBD in melatonin gummies sold in the US, JAMA, 2023pubmed.ncbi.nlm.nih.gov
- Burkhardt S and others, Detection and quantification of the antioxidant melatonin in Montmorency and Balaton tart cherries, Journal of Agricultural and Food Chemistry, 2001pubmed.ncbi.nlm.nih.gov
- American Academy of Pediatrics, HealthyChildren.org, Melatonin and children's sleep, last updated January 22, 2026healthychildren.org
